Patent application title: METHOD OF PRODUCING FERMENTED TEA DRINK

Abstract:

Disclosed is a process for preparing a fermented tea drink comprising the
steps of: adding water to fresh tea leaves and milling the mixture;
removing a solid fraction from the mixture; and heating the liquid, or
adding water to fresh tea leaves and milling the mixture; incubating the
mixture with shaking for 1 to 40 minutes; removing a solid fraction from
the mixture; and heating the liquid; to obtain the fermented tea drink.
Catechins can be efficiently converted into theaflavin to provide a
fermented tea drink that has a high content of theaflavin, theasinensins
A and B, and gallic acid, that exhibits little bitterness and
astringency, that is entirely free of cream down, and that has an
excellent aroma and sweetness.

Claims:

1. A process for preparing a fermented tea drink that substantially free
of epigallocatechin gallate and epicatechin gallate, comprising the steps
of:adding water to fresh tea leaves and milling the mixture; removing a
solid fraction from the mixture; and heating the liquid, oradding water
to fresh tea leaves and milling the mixture; incubating the mixture with
shaking for 1 to 40 minutes; removing a solid fraction from the mixture;
and heating the liquid;to obtain the fermented tea drink.

2. A process for preparing a fermented tea concentrate that substantially
free of epigallocatechin gallate and epicatechin gallate, comprising the
steps of:adding water to fresh tea leaves and milling the mixture;
removing a solid fraction from the mixture; heating the liquid; and
concentrating the liquid; oradding water to fresh tea leaves and milling
the mixture; incubating the mixture with shaking for 1 to 40 minutes;
removing a solid fraction from the mixture; and heating the liquid; and
concentrating the liquid;to obtain the a fermented tea concentrate.

3. The process according to claim 1, wherein the shaking step is carried
out for 5 minutes to 40 minutes.

4. The process according to claim 1, wherein the milling step is carried
out for 1 second to 20 minutes.

5. The process according to claim 1, wherein the incubation step is
carried out in the presence of at least five-fold (w/w) water with
reference to the fresh tea leaves.

6. The process according to claim 5, wherein the incubation step is
carried out in the presence of at least seven-fold (w/w) water with
reference to the fresh tea leaves.

7. The process according to claim 1, wherein stems of tea leaves are used
as the fresh tea leaves.

8. A fermented tea drink that substantially free of epigallocatechin
gallate and epicatechin gallate, obtained by a process comprising the
steps of:adding water to fresh tea leaves and milling the mixture;
removing a solid fraction from the mixture; and heating the liquid,
oradding water to fresh tea leaves and milling the mixture; incubating
the mixture with shaking for 1 to 40 minutes; removing a solid fraction
from the mixture; and heating the liquid.

9. A fermented tea concentrate that substantially free of epigallocatechin
gallate and epicatechin gallate, obtained by a process comprising the
steps of:adding water to fresh tea leaves and milling the mixture;
removing a solid fraction from the mixture; heating the liquid; and
concentrating the liquid; oradding water to fresh tea leaves and milling
the mixture; incubating the mixture with shaking for 1 to 40 minutes;
removing a solid fraction from the mixture; and heating the liquid; and
concentrating the liquid.

10. The process according to claim 2, wherein the shaking step is carried
out for 5 minutes to 40 minutes.

11. The process according to claim 2, wherein the milling step is carried
out for 1 second to 20 minutes.

12. The process according to claim 2, wherein the incubation step is
carried out in the presence of at least five-fold (w/w) water with
reference to the fresh tea leaves.

13. The process according to claim 12, wherein the incubation step is
carried out in the presence of at least seven-fold (w/w) water with
reference to the fresh tea leaves.

14. The process according to claim 2, wherein stems of tea leaves are used
as the fresh tea leaves.

Description:

RELATED APPLICATION

[0001]This application claims priority based on Japanese Patent
Application No. 2008-87504 filed 28 Mar. 2008, the contents of which are
hereby incorporated by reference.

TECHNICAL FIELD

[0002]The present invention relates to a process for preparing a fermented
tea drink.

BACKGROUND ART

[0003]Primarily four catechins (epicatechin (EC), epigallocatechin (EGC),
epicatechin gallate (ECG), and epigallocatechin gallate (EGCG)) are
present in tea leaves, and four theaflavins (theaflavin (TF),
theaflavin-3-O-gallate (TF3-G), theaflavin-3'-O-gallate (TF3'-G), and
theaflavin-3,3'-di-O-gallate (TFDG)) are produced by the catechin
combinations indicated below during the process of producing black tea,
i.e., during the fermentation process.

EC+EGC→TF

EC+EGCG→TF3-G

ECG+EGC→TF3'-G

ECG+EGCG→TFDG

[0004]The following methods are generally used to obtain fermented tea:
methods in which the tea leaves are fermented in slurry form; methods in
which the tea leaves are ground, a small quantity of water is added, and
stirring with shaking is performed. In these methods, the four catechins
cited above undergo oxidative polymerization under the effect of the
polyphenol oxidase present in the tea leaves, resulting in the production
of theaflavin and three types of theaflavin gallate. However, these
methods have various drawbacks such as bitterness and astringency, cream
down, and a dark red color occur due to the residual EGCG and ECG.

[0005]The presence of gallate group contributes in generation of a bitter
and astringent taste in fermented tea drinks. For example, the ECG and
EGCG in green tea are strongly bitter and astringent, while the EC and
EGC are lightly bitter. A bitter and astringent taste is produced when
green tea catechins remain present in black tea. In addition, with regard
to black tea, the presence of EGCG, ECG, TF3G, TF3'G, and TFDG in black
tea causes cream-down. EGCG and ECG have a particularly prominent
influence on cream-down. In order to solve these problems, a method has
been developed where the bitter and astringent taste is reduced through
cleavage of the gallate group in EGCG, ECG, TF3G, TF3'G, and TFDG by the
addition of tannase during the fermentation step (see, for example,
Japanese Patent Application Laid-open No. H11-225672). Another method
involves addition of a solution of enzymes such as cellulase,
hemicellulase, and protopectinase that disrupt tea leaf tissue in the
fermentation process of fresh tea leaves (see, for example, Japanese
Patent Application Laid-open No. 2004-113090).

[0006]The reference documents cited in the application are as indicated
below. The contents of these documents are hereby incorporated by
reference in its entirety.

[0007]An object of the present invention is to provide a process for
preparing a fermented tea drink that is rich in theaflavin,
theaflavin-3-O-gallate, theaflavin-3'-O-gallate, and
theaflavin-3,3'-di-O-gallate, that contains almost none of the
bitter/astringent components epigallocatechin gallate, epicatechin
gallate, epigallocatechin, and epicatechin, wherein the tea drink
exhibits little bitterness and astringency, is free of cream-down, and
has an excellent aroma and sweetness, as well as to provide a process for
preparing a fermented tea concentrated solution and a powdered fermented
tea concentrate.

[0008]The inventor discovered that a black tea-flavored fermented tea
drink that substantially free of epigallocatechin gallate and epicatechin
gallate, that exhibits little bitterness and astringency, that exhibits
an excellent sweetness and aroma, and that is entirely free of cream down
can be obtained by adding a large amount of water to fresh, unwithered
tea leaves and milling with a mixer, removing a solid fraction therefrom
and heating, or by adding a large amount of water to fresh tea leaves and
milling, shaking for a short period of time, and removing a solid
fraction therefrom and heating. That is, the present invention provides a
process for preparing a fermented tea drink, comprising the steps of:
adding water to fresh tea leaves and milling for 1 second to 40 minutes,
preferably 5 to 20 minutes, removing a solid fraction from the mixture,
and heating the liquid, or the steps of adding water to fresh tea leaves
and milling with a mixer for 1 second to 20 minutes, preferably 3 to 5
minutes, shaking the mixture for 1 to 60 minutes, preferably 3 to 40
minutes, removing a solid fraction from the mixture, and heating the
liquid. As used herein, "substantially free of epigallocatechin gallate
and epicatechin gallate" means that the total quantity of
epigallocatechin gallate and epicatechin gallate in the product is less
than 0.1% with reference to the weight of the starting fresh tea leaves,
and also means that peaks for these substances are not observed in
ordinary high-performance liquid chromatographic (HPLC) analysis, such as
that used in the examples provided herebelow. In addition, incubation is
preferably carried out with the addition of at least five-fold water
(w/w; on a weight basis with respect to the fresh tea leaves), and more
preferably with the addition of at least seven-fold water (w/w).
According to the present invention, a fermented tea drink can be obtained
by efficiently converting all of the catechins to theaflavin-3-O-gallate,
theaflavin-3'-O-gallate, theaflavin-3,3'-di-O-gallate, and theaflavin as
the main component, without the exogenous addition of enzymes such as
tannase or tea leaf tissue disrupting enzymes.

[0009]According to the process of the present invention, the four
catechins (EC, EGC, ECG, EGCG) in tea leaves that will cause a bitter and
astringent taste are almost entirely converted to catechine polymers
including theaflavin, theaflavin-3-O-gallate, theaflavin-3'-O-gallate,
and theaflavin-3,3'-di-O-gallate and theasinensins A and B. As a
consequence, the fermented tea drink produced according to the present
invention has a bright orange color and an enhanced sweetness and aroma,
and exhibits a mild flavor with almost no bitterness and astringency
because it is almost entirely free of the epigallocatechin gallate,
epicatechin gallate, epigallocatechin, and epicatechin that are
bitterness and astringency components. In addition, the fermented tea
drink thus obtained exhibits an excellent storage stability. With
reference to the four theaflavins, the fermented tea drink of the present
invention has a particularly high TF content and a low content of TF3G,
TF3'G, and TFDG, and is free of EGCG and ECG which may cause creaming,
and thus the fermented tea drink of the present invention does not
undergo cream-down. Tannase is frequently added to conventional fermented
tea drinks in order to prevent creaming. In contrast, a fermented tea
drink completely free of the creaming phenomenon can be produced
according to the present invention through the combined reactions of the
various enzymes present in the fresh tea leaves. In experiments at the
cellular level, theaflavin has been reported to have much higher platelet
aggregation inhibitory activity than EGCG and a higher activity than
TF3G, TF3'G, and TFDG. Moreover, a high antioxidation activity, a high
antibacterial activity, and a high blood sugar lowering activity have
also been reported. However, the theaflavin content in conventional black
tea leaves is as low as 0.08%. The theaflavin content in the fermented
tea drink produced according to the present invention is much higher than
conventional tea drinks. Thus, the fermented tea drink of the present
invention is expected to serve as a health drink for the prevention of
lifestyle diseases, for example, in individuals with a risk of thrombosis
or high blood sugar level.

PREFERRED EMBODIMENT OF THE INVENTION

[0010]The fresh tea leaves used in the process of the present invention
refer to tea leaves after harvested but prior to execution of the
withering step, and also refer to tea leaves frozen after harvesting but
prior to the execution of the withering step. The fresh tea leaves
encompass both fresh tea leaves and stems, which may be used separately
or in combination. The starting fresh tea leaves may be tea leaves of any
of the green tea and black tea cultivars in general cultivation. Examples
of typical tea leaves in cultivation in Japan include asatsuyu, yabukita,
yamatomidori, makinoharawase, kanayamidori, okumidori, ooiwase,
okuhikari, meiryoku, samidori, komakage, yamanami, minekaori,
hatsumomiji, benifuuki, benihomare, and benihikari. The present invention
is not limited to these cultivars, and tea leaves from any cultivar grown
domestically or overseas can also be used. The fresh tea leaves may be
used immediately after harvest or may be frozen immediately after harvest
and stored before use. The tea leaf harvest time can be first flush,
second flush, third flush, or fourth flush. The catechin quantities and
the activities of the polyphenol oxidase, peroxidase, tannase, and
hydrolytic enzymes vary with harvest, and the process conditions are
preferably controlled as appropriate depending on the particular quality
of tea leaf used. When the cost, catechin quantity, enzymatic activity,
and so forth are comprehensively evaluated, second flush teas are
desirable for the tea leaf used in the process of the present invention.
In the case of fourth flush teas, the catechin quantity and enzymatic
activity are fairly inferior, but the enzymes may be activated when the
tea leaves are held for several days at room temperature after
harvesting, thus yielding a fermented tea with an excellent taste and
aroma. In addition, after the tea leaves are incubated with shaking, an
antioxidant (for example, ascorbic acid, sodium ascorbate, or a fruit
juice such as lemon juice) may be added to the shaken liquid in order to
prevent oxidation of the theaflavins.

[0011]In the process of the present invention, first, water is added to
the fresh tea leaves prior to the withering step and the fresh tea leaves
are milled in water using, for example, a mixer. Preferably the milling
step is carried out after the water is added to the tea leaves. If the
water is added after the tea leaves have been milled in air, the
components present in the cells of the tea leaves will not transfer well
into the aqueous phase and the fermentation may not develop adequately.
The milling step can be carried out at a temperature from 0° C. to
30° C. After milling, the mixture is incubated with shaking
without separating the water from the tea leaves. When water is added to
the fresh tea leaves and milled, components present in the cells of the
tea leaves, e.g., polyphenol oxidase, peroxidase, tannase, hydrolytic
enzymes, and various tea components such as catechins and caffeine will
leach into the water. When the liquid containing these enzymes and
components have leached is subjected to shake incubation, the catechins
are converted into theaflavins by the action of these enzymes.

[0012]Peroxidase is an enzyme that produces theaflavin in the presence of
hydrogen peroxide. In the process of the present invention, hydrogen
peroxide need not to be added because it is produced metabolically.
Polyphenol oxidase is an enzyme that produces theaflavins in the presence
of oxygen. Tannase can cleave off the gallate group of catechins and
theaflavins. Cleavage of the gallate group also occurs by the action of
the hydrolytic enzymes. Gallic acid is produced by these reactions. In
addition, theasinensin A is produced by the dehydrogenation and
condensation of two EGCGs through their pyrogallol rings, while
theasinensin B is produced by dehydrogenation and condensation between
EGCG and EGC through their pyrogallol rings.

[0013]In the process of the present invention, shaking step is carried out
for a short period of time after the addition of water to the fresh tea
leaves and milling without a solid/liquid separation. When a large
quantity of water is added to the fresh, unwithered tea leaves, milled
with a mixer for 1 second to 5 minutes, and incubated with shaking for 1
to 40 minutes, most of the four catechins present in the fresh tea leaves
is converted to theaflavins. In addition, when water is added to the
fresh tea leaves and milled with a mixer for 1 second to 40 minutes,
preferably 5 to 20 minutes, most of the four catechins present in the
fresh tea leaves are converted to theaflavins. The mixer used herein is a
household mixer (blender) with a capacity of approximately 700 to 1000 mL
and an output power of about 200 to 300 W. When the process of the
present invention is scaled up to the industrial production level, those
skilled in the art can select a suitable milling time in view of the
device used and the quantity to be processed. An example of an industrial
production mixer that can be used in the process of the present invention
is a commercial mixer (blender) with a capacity of approximately 4000 mL
and an output power of about 1400 W, with the revolving speed of high
speed (18,500 rpm), medium speed (16,300 rpm), or low speed (14,000 rpm).
A custom-made blender may be used when even greater scale is desired, or
the mixing process may be repeated in conformity to the quantity of tea
leaves. Any device capable of milling can be used to mill the fresh tea
leaves, and examples include mixers, ultramizers, hammer mills,
homogenizers, and so forth, where mixers (blenders) are particularly
preferred.

[0014]The shaking time will vary depending on the type of tea leaf used,
the water content, the storage conditions, and so forth, but is
preferably from 1 minute to 40 minutes, more preferably from 5 minutes to
30 minutes, and even more preferably from 3 minutes to 20 minutes. When
shaking is continued for a long period of time, for example, for 1 hour
or more, the generated theaflavins undergo oxidation or polymerization.
As a consequence the content of the theaflavins in the fermented tea
undergoes a sharp decline, the fermented tea has a weak aroma, and a
perception of bitterness will occur. The optimal shaking time will vary
with the tea leaf used, and those skilled in the art can easily optimize
the conditions. The shaking temperature should be within the temperature
range in which the enzymes can function, but is not otherwise
particularly limited, and is, for example, from 10° C. to
40° C. and preferably from 20° C. to 30° C.

[0015]The quantity of water added to the fresh tea leaves can be selected
as appropriate depending on the type of tea leaves used, the water
content, the storage conditions, and so forth, but is preferably from 5
mL to 500 mL per 1 g fresh tea leaves, more preferably from 7 mL to 200
mL per 1 g fresh tea leaves, and even more preferably from 10 mL to 100
mL per 1 g fresh tea leaves. At less than 5 mL, the quantity of
theaflavins production will decline, while at more than 500 mL the
resulting fermented tea will have little flavor. In addition, a green tea
extract may be used in addition to the water or in place of the water. An
aqueous solution that contains four catechins can be used as the green
tea extract, for example, a liquid prepared by the addition of water to
heat-processed green tea leaves and extraction; a liquid prepared by the
addition of water to heat-processed green tea leaves, extraction,
concentration to give a tea extract, and addition of water to the tea
extract; and a liquid prepared by the addition of water to a tea extract.

[0016]After milling the tea leaves with a mixer for a desired period of
time followed by shake incubation or after milling the tea leaves with a
mixer for a desired period of time, the reaction mixture is filtered to
remove the solid fraction from liquid. The filtration step may be carried
out by gravity filtration or by suction filtration under reduced
pressure. Alternatively, the solid fraction may be removed by
centrifugation. If the filtrate is cloudy and does not become transparent
after filtration or centrifugation, the filtrate may be left stand for
about a day and then processed by gravity filtration, suction filtration
under reduced pressure, or centrifugation. The resulting solution will
have an orange or bright red color. The liquid is bottled and heated at
from 95° C. to 100° C. for from about 5 to 10 minutes on a
hot water bath with an aluminum foil capping for preventing a loss of
aroma; and then allowed stand at room temperature to obtain a fermented
tea drink. An autoclave treatment for 1 to 20 minutes at 120° C.
may be employed instead of heating on a hot water bath. When the process
of the present invention is to be scaled up to the level of industrial
production, a crude filtration may be carried out by conventional methods
followed by filtration using, for example, a Sharples centrifuge. In the
case of producing a canned drink, the product is subjected to retort
sterilization according to the requirements of the Food Sanitation Act.
In the case of plastic bottles, tube sterilization or plate sterilization
by the hot pack filling method may be employed. After the heat treatment,
the liquid is subjected to a concentration step, e.g., vacuum
concentration, spray drying, freeze drying to produce a concentrated
liquid or powdered extract. The product can be provided as food products
in various forms or as raw materials in various industries, such as food
supplements, health care products, confectionary, pharmaceuticals, and
food products.

[0017]The contents of all of the patents and reference documents
explicitly cited in the application are hereby incorporated by reference
in its entirety.

EXAMPLES

[0018]The present invention is described in greater detail by the examples
provided below, but the present invention is not limited by these
examples. The contents of EC, ECG, EGC, EGCG, TF, TF3G, TF3'G, and TFDG
were analyzed using an HPLC instrument (JASCO, PU-980, UV-970) and an
ODS120A column (TOSO, 4.6 mm×250 mm). The HPLC conditions were as
follows: solvent=acetonitrile: ethyl acetate: 0.05% H3PO4=21:
3: 76; flow rate=1.0 mL/min; temperature=25° C. Detection with 280
nm W. The measurements were calculated with respective calibration
curves.

Example 1

Example of the Use of Five-Fold Water with Respect to the Fresh Tea Leaves
and Milling for 8 Minutes

[0019]125 mL distilled water was added to 25.0 g benifuuki tea leaves
harvested on 3 July and milled for 8 minutes using a household mixer. The
mixture was filtered by suction filtration and the filtrate was
transferred to a glass bottle, which was capped with aluminum foil. This
was followed by autoclaving at 120° C. for 20 minutes and then
standing at room temperature. Analysis by HPLC gave 63 mg TF (0.063%), 11
mg TF3G (0.011%), 4.5 mg TF3'G (0.0045%), 1.6 mg TFDG (0.0016%), 0 g EGCG
(0%), 0 g ECG (0%), and 432 mg caffeine (0.43%) per 100 g fresh leaves.

Example 2

Example of the Use of Eight-Fold Water with Respect to the Fresh Tea
Leaves and Milling for 8 Minutes

[0020]200 mL distilled water was added to 24.89 g benifuuki tea leaves
harvested on 3 July and milled for 8 minutes using a household mixer. The
mixture was filtered by suction filtration and the filtrate was
transferred to a glass bottle, which was capped with aluminum foil. This
was followed by autoclaving at 120° C. for 20 minutes and then
standing at room temperature. Analysis by HPLC gave 127 mg TF (0.13%),
22.2 mg TF3G (0.022%), 8.1 mg TF3'G (0.008%), 3.7 mg TFDG (0.0037%), 0 g
EGCG (0%), 0 g ECG (0%), and 558 mg caffeine (0.56%) per 100 g fresh
leaves.

Example 3

Example of the Use of Eight-Fold Water with Respect to the Fresh Tea
Leaves and Milling for 15 Minutes

[0021]200 mL distilled water was added to 24.89 g benifuuki tea leaves
harvested on 3 July and milled for 15 minutes using a household mixer.
The mixture was filtered by suction filtration and the filtrate was
transferred to a glass bottle, which was capped with aluminum foil. This
was followed by autoclaving at 120° C. for 20 minutes and then
standing at room temperature. Analysis by HPLC gave 73.4 mg TF (0.073%),
14.1 mg TF3G (0.014%), 5.0 mg TF3'G (0.005%), 2.8 mg TFDG (0.0028%), 0 g
EGCG (0%), 0 g ECG (0%), and 505 mg caffeine (0.51%) per 100 g fresh
leaves.

Example 4

Example of the Use of Ten-Fold Water with Respect to the Fresh Tea Leaves
and Shaking for 5 Minutes after Milling for 5 Minutes

[0022]100 mL distilled water was added to 10 g benifuuki second flush tea
harvested on 23 July and this was milled for 5 minutes using a household
mixer and then shaken (120 rpm) for 5 minutes at room temperature and
subjected to suction filtration. The obtained filtrate was transferred to
a glass bottle, which was capped with aluminum foil. This was followed by
heating on a hot water bath at 100° C. for 10 minutes and then
standing at room temperature. Analysis by HPLC gave 257 mg TF (0.26%),
92.7 mg TF3G (0.093%), 49.2 mg TF3'G (0.049%), 48.1 mg TFDG (0.048%), and
495 mg caffeine (0.50%) per 100 g fresh leaves.

Example 5

Example of the Use of Ten-Fold Water with Respect to the Fresh Tea Leaves
and Shaking for 35 Minutes after Milling for 8 Minutes

[0023]200 mL distilled water was added to 19.13 g benifuuki second flush
tea harvested on 23 July and milled for 8 minutes using a household mixer
and then shaken (120 rpm) for 35 minutes at room temperature and
subjected to suction filtration. The obtained filtrate was transferred to
a glass bottle, which was capped with aluminum foil. This was followed by
heating on a hot water bath at 100° C. for 10 minutes and then
standing at room temperature. Analysis by HPLC gave 236 mg TF (0.24%),
62.7 mg TF3G (0.063%), 26 mg TF3'G (0.026%), 23.5 mg TFDG (0.024%), and
590 mg caffeine (0.59%) per 100 g fresh leaves.

Example 6

Example of the Use of Eight-Fold Water with Respect to the Fresh Tea
Leaves and Shaking for 30 Minutes after Milling for 3 Minutes

[0024]218 mL distilled water was added to 26.68 g yabukita tea leaves
harvested on 15 June and milled for 3 minutes using a household mixer and
then shaken for 30 minutes at room temperature and subjected to suction
filtration. The obtained filtrate was transferred to a glass bottle,
filtered by suction filtration. The obtained filtrate was transferred to
a glass bottle, sodium ascorbate was added, and the glass bottle was
capped with aluminum foil. This was followed by heating on a hot water
bath at 100° C. for 10 minutes and then standing at room
temperature. Analysis by HPLC gave 176 mg TF (0.18%), 106 mg TF3G
(0.11%), 74.0 mg TF3'G (0.074%), 106 mg TFDG (0.11%), 200 mg caffeine
(0.20%), 0 g EGCG (0%), and 0 mg ECG (0%) per 100 g fresh leaves.

Example 7

Scale Up Example: Example of the Use of Eight-Fold Water with Respect to
Frozen Fresh Tea Leaves and Shaking for 40 Minutes After Milling for 3
Minutes

[0025]306 g yabukita tea leaves harvested on 15 June were packed in an
aluminum vacuum pack and were frozen and stored at -78° C. After 1
week, 4 L water was added to 76.5 g of the tea leaves that had been
stored frozen and milled for 3 minute in an industrial mixer (high
speed). The mixture was transferred to a 30-L stainless steel tank. The
entire quantity of tea leaves (306 g) was milled by repeating this
process for 4 times, and 9 L water was added to bring the total quantity
of water to 25 L. The mixture was shaken for 40 minutes. After crude
filtration, Na ascorbate was added and filtered, and then subjected to
retort sterilization. Analysis by HPLC gave 1.9 g TF (0.19%), 1.2 g TF3G
(0.12%), 800.0 mg TF3'G (0.08%), 1.1 g TFDG (0.11%), 2 g caffeine
(0.20%), 0 g EGCG (0%), and 0 mg ECG (0%) per 1 kg tea leaves.

Example 8

Example of a Freeze-Dried Article Obtained by Using Ten-Fold Water with
Respect to the Fresh Tea Leaves, Milling for 5 Minutes, and then Shaking
for 5 Minutes

[0026]100 mL distilled water was added to 10 g benifuuki second flush tea
harvested on 23 July and milled for 5 minutes using a household mixer and
then shaken (120 rpm) for 5 minutes at room temperature and subjected to
suction filtration. The obtained filtrate was transferred to a glass
bottle, which was capped with aluminum foil. This was followed by heating
on a hot water bath at 100° C. for 10 minutes and then freeze
drying to obtain a product of 1.5 g. Analysis by HPLC gave 23 mg TF
(1.5%), 8 mg TF3G (0.53%), 3 mg TF3'G (0.2%), 5 mg TFDG (0.33%), and 45
mg caffeine (3.0%) per 1.5 g product.

Example 9

[0027]300 mL water was added to 20.5 g stems of benifuuki harvested on 15
July and milled for 3 minutes using a household mixer, transferred to a
100-mL Erlenmeyer flask, and then shaken for 30 minutes. After crude
filtration, Na ascorbate was added and filtered, and then subjected to
retort sterilization. 30 mg TF (0.03%), 10 mg TF3G (0.01%), 7 mg TF3'G
(0.007%), 5 mg TFDG (0.005%), and 96 mg caffeine (0.1%) were obtained per
100 g fresh stems.

Comparative Example 1

Example of Milling in Air, Addition of 3.8-Fold Water, and Shaking for 1
Hour

[0028]8.55 g benifuuki tea leaves harvested on 23 July were milled with a
household mixer followed by the addition of 32.7 mL distilled water and
stirring by shaking for 1 hour at room temperature. The mixture was
filtered under reduced pressure and the filtrate was transferred to a
glass bottle, which was capped with aluminum foil. This was heated at
100° C. for 10 minutes and then allowed to stand at room
temperature. Analysis by HPLC gave 98 mg TF (0.098%), 29 mg TF3G
(0.029%), 10 mg TF3'G (0.010%), 3 mg TFDG (0.003%), 200 mg EGCG (0.2%), 0
mg ECG (0%) and 220 mg caffeine (0.22%) per 100 g fresh leaves.

Comparative Example 2

Example of Milling in Air, Addition of Ten-Fold Water, and Shaking for 1
Hour

[0029]11.86 g yabukita tea leaves harvested on 18 July were milled with a
mixer followed by the addition of 118 mL distilled water and shaking for
60 minutes at room temperature. The mixture was filtered by suction
filtration and the filtrate was transferred to a glass bottle, which was
capped with aluminum foil. This was heated on a hot water bath at
100° C. for 10 minutes and then allowed to stand at room
temperature. Analysis by HPLC gave 108 mg TF (0.11%), 15.2 mg TF3G
(0.015%), 21 mg TF3'G (0.021%), 5.8 mg TFDG (0.006%), 176 mg caffeine
(0.18%) 1.94 g EGCG (1.9%), and 56.8 mg ECG (0.057%) per 100 g fresh
leaves.

[0030]The tea drinks obtained in the examples and comparative examples
were evaluated by 5 panelists for aroma, water color, body, sweetness,
and bitterness and astringency.

Example 1

[0031]aroma: sweet aroma

[0032]water color: dark orange color

[0033]body: appropriate

[0034]bitterness and astringency: a somewhat bitter and astringent taste
is present

[0035]sweetness: a slight sweetness is perceived

[0036]Comprehensive evaluation: while a faint sweet aroma is perceived,
when held in the mouth, there is a slight residual bitter and astringent
taste. There is a sweet perception to some degree, and a soothing effect
can be expected.

Example 2

[0037]aroma: sweet aroma

[0038]water color: dark orange color

[0039]body: appropriate

[0040]bitterness and astringency: a somewhat bitter and astringent taste
is present

[0041]sweetness: sweetness is perceived

[0042]Comprehensive evaluation: while a very sweet aroma is perceived,
when held in the mouth, there is a slight residual bitter and astringent
taste. There is a sweet perception, and a soothing effect can be
expected.

Example 3

[0043]aroma: sweet aroma

[0044]water color: dark orange color

[0045]body: appropriate

[0046]bitterness and astringency: very weak

[0047]sweetness: sweetness is perceived

[0048]Comprehensive evaluation: while a very sweet aroma is perceived,
when held in the mouth, the bitter and astringent taste is very weak;
mild with a sweet perception; a soothing effect can be expected; very
good balance as a whole.

Example 4

[0049]aroma: the sweet aroma of tea with milk or a green tea-milk

[0050]water color: dark orange color

[0051]body: appropriate

[0052]bitterness and astringency: very weak

[0053]sweetness: sweetness similar to tea with milk or a green tea-milk

[0054]Comprehensive evaluation: while the sweet aroma of tea with milk or
a green tea-milk is perceived, when held in the mouth, the bitter and
astringent taste is very weak; the rich sweetness of tea with milk or a
green tea-milk is perceived; a soothing effect can be expected; very good
balance as a whole.

Example 5

[0055]aroma: the sweet aroma of tea with milk or a green tea-milk

[0056]water color: dark orange color

[0057]body: appropriate

[0058]bitterness and astringency: very weak

[0059]sweetness: sweetness similar to tea with milk or a green tea-milk

[0060]Comprehensive evaluation: while the sweet aroma of tea with milk or
a green tea-milk is perceived, when held in the mouth, the bitter and
astringent taste is very weak; the rich sweetness of tea with milk or a
green tea-milk is perceived; a soothing effect can be expected; very good
balance as a whole.

Example 6

[0061]aroma: aroma sensed as sweetness

[0062]water color: dark orange color

[0063]body: appropriate

[0064]bitterness and astringency: very weak

[0065]sweetness: appropriate sweetness

[0066]Comprehensive evaluation: while a soothing sensation is experienced
due to the sweet aroma, when held in the mouth, the bitter and astringent
taste is very weak; there is a perception of body and sweetness; a
soothing effect can be expected; very good balance as a whole.

Example 7

[0067]aroma: aroma sensed as sweetness

[0068]water color: dark orange color

[0069]body: appropriate

[0070]bitterness and astringency: very weak

[0071]sweetness: appropriate sweetness

[0072]Comprehensive evaluation: while a soothing sensation is experienced
due to the sweet aroma, when held in the mouth, the bitter and astringent
taste is very weak; there is a perception of body and sweetness; a
soothing effect can be expected; very good balance as a whole.

Example 9

[0073]aroma: aroma sensed as sweetness

[0074]water color: dark orange color

[0075]body: appropriate

[0076]bitterness and astringency: very weak

[0077]sweetness: appropriate sweetness

[0078]Comprehensive evaluation: while a soothing sensation is experienced
due to the sweet aroma, when held in the mouth, the bitter and astringent
taste is very weak; there is a perception of body and sweetness; a
soothing effect can be expected; very good balance as a whole.

Comparative Example 1

[0079]aroma: weak aroma

[0080]water color: blackish red, lack of transparency

[0081]body: appropriate

[0082]bitterness and astringency: bitterness is perceived

[0083]sweetness: weak sweetness

[0084]Comprehensive evaluation: weak aroma; when held in the mouth, a
bitter and astringent taste is perceived, almost no sense of sweetness.

Comparative Example 2

[0085]aroma: weak aroma

[0086]water color: dark orange color

[0087]body: appropriate

[0088]bitterness and astringency: bitterness is detected

[0089]sweetness: weak sweetness

[0090]Comprehensive evaluation: weak aroma; when held in the mouth,
bitterness and astringency are detected, while almost no sweetness is
perceived.

Example 10

[0091]Yabukita tea leaves harvested on 7 October (fourth flush tea) were
allowed to stand for 4 days at room temperature; 140 mL distilled water
was then added to 14.76 g of the tea leaves and milled for 1 minute using
a household mixer and then shaken for 37 minutes (120 rpm) at room
temperature. 150 mg sodium ascorbate was then added. The mixture was
filtered by suction filtration and the filtrate was transferred to a
glass bottle, which was capped with aluminum foil. This was followed by
heating on a hot water bath at 100° C. for 10 minutes and then
standing at room temperature. HPLC analysis gave 132.4 mg TF (0.13%),
46.0 mg TF3G (0.046%), 33 mg TF3'G (0.033%), 24 mg TFDG (0.024%), and 261
mg caffeine (0.26%) per 100 g fresh leaves.

[0092]The obtained tea drink was evaluated by 5 panelists for aroma, water
color, body, sweetness, and bitterness and astringency.

[0093]aroma: the aroma is perceived as an agreeable sweetness resembling
herbal tea; the aroma is perceived as soothing

[0094]water color: dark orange color

[0095]body: appropriate

[0096]bitterness and astringency: very weak

[0097]sweetness: appropriate sweetness

[0098]Comprehensive evaluation: while a soothing sensation is experienced
due to the fragrant aroma, when held in the mouth, the bitter and
astringent taste is very weak; there is a perception of body and
sweetness; a soothing effect can be expected; very good balance as a
whole. In comparison to the creamy taste of second flush tea, fourth
flush tea has a thin body and on the whole has a clean finish.